Cochlear Implants Can Lead to Normal School, Work Life

Action Points

Explain to interested patients that neither study included children with sensorineural hearing loss who didn't get cochlear implants, which precludes drawing causal conclusions that the implants led to better outcomes that the children would have had with hearing aids alone.

Severely hearing-impaired youngsters who get cochlear implants may not catch up to their peers right away in language comprehension or general schoolwork, but their ultimate educational and employment expectations can be good, two independent studies have found.

Both concluded that earlier implants are better than later ones.

In a prospective French study of children who received their cochlear implant before age 6, some 53% failed at least one grade at school.

But among those followed to college age, half entered university with their normal-hearing peers and the rest got vocational training, according to Frederic Venail, MD, PhD, of the Centre Hospitalier Universitaire Gui de Chauliac in Montpellier, France, and colleagues.

An earlier start -- with implantation at a younger age -- appeared important, they reported in the April Archives of Otolaryngology -- Head & Neck Surgery.

That endorsement was echoed by a second prospective study showing more rapid acquisition and comprehension of speech with earlier implantation.

The gains were greater than would have been expected from preimplantation scores, John K. Niparko, MD, of Johns Hopkins, and colleagues reported in the April 21 Journal of the American Medical Association.

"Early implantation may take advantage of neuronal flexibility inherent in critical periods of auditory-based learning," they wrote. But until sufficient long-term data are available, though, timing of implantation will remain an unsettled issue, they cautioned.

Their Childhood Development after Cochlear Implantation (CDaCI) study of spoken language outcomes included 188 children with severe to profound sensorineural hearing loss who got an implant before age 5 at one of six U.S. centers.

Compared with 97 hearing children of similar ages at two preschools, the implant recipients did not reach age-appropriate spoken language scores on the Reynell Developmental Language Scale after three years (mean deficit 22.3 points in comprehension and 19.8 in expression).

However, the implants were associated with greater improvement than predicted by preimplantation baseline scores in speech (8.4 versus 5.8 predicted points per year) and speech comprehension (10.4 versus 5.4 predicted points per year).

Each year of younger age at cochlear implantation predicted a 1.1-point-per-year greater gain in comprehension and 1.0-point-per-year steeper rise in expression scores.

Likewise, each one-year shorter duration of hearing deficit for a child was associated with steeper rate increases in speech and comprehension (0.6 and 0.8 points per year shorter, respectively).

In fact, the trajectories for those implanted before 18 months of age were similar to those with normal hearing.

The researchers cautioned that their study was limited in making causal conclusion by its observational design and absence of a control group of deaf children without implants.

They recommended close monitoring of performance with hearing aids to see if it is sufficient to allow spoken language acquisition to progress.

But, they said their findings "suggest that delaying implantation to extend hearing aid use for children with severe to profound hearing loss may be detrimental to language development following cochlear implantation."

Venail's group agreed.

"In an ideal situation, cochlear implantation should also allow recipients to integrate into the hearing world and improve their quality of life," they wrote in the Archives.

Since education and employment are two key long-term measures of this integration, they prospectively examined outcomes for 100 prelingually deaf children who got an implant before age 6 at a tertiary care center in France and who had at least four years of follow-up.

Among the 74 without additional disabilities, 26% had delayed reading and writing skill acquisition and 53% failed at least one grade at school (most were at mainstream schools full-time), "perhaps reflecting the language impairment remaining during the first years after cochlear implantation."

Compared with the age-matched French population, implant recipients ages 16 to 18 were more likely to be in the workforce (11% versus 6.3%).

Vocational education was also more likely in those who had received a cochlear implant (17% versus 2.4% in the general population ages 12 to 15 and 44% versus 26.6% ages 16 to 18).

The eight participants over age 18 were also more likely to have a high school diploma (62% versus 53% among the general population) despite the fact that half had failed at least one grade at school.

Children with additional disabilities who got a cochlear implant had more varying trajectories. Only half were able to enter mainstream schools and 73% failed at least one grade at school.

Among them, 19% continued to use sign language as their everyday form of communication with family compared with only 1% in those without additional disabilities.

"Although these students may underachieve as measured in academic terms, most do reach some degree of social and communicative autonomy, an improvement that demonstrates the benefit of cochlear implantation in this population," Vernail's group wrote in the paper.

Venail's group reported no conflicts of interest.

The CDaCI was supported by a grant from the National Institute on Deafness and Other Communication Disorders, the CityBridge Foundation, and the Sidgmore Family Foundation.

Warranties on the implant devices used by children with implants in this study were discounted by 50% by the Advanced Bionics Corporation, Cochlear Corporation, and the MedEl Corporation.

Niparko reported serving on advisory boards without remuneration for two cochlear implant manufacturers, Advanced Bionics Corporations and the Cochlear Corporation, and serving on the board of directors for a school for children with hearing loss that has received gifts from cochlear implant manufacturers.

External advisers received honoraria for their review of the study protocol and progress reports.

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